[6-K] GERDAU S.A. Current Report (Foreign Issuer)

U.S. SECURITIES AND EXCHANGE COMMISSION 

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER 

PURSUANT TO RULE 13a-16 OR 15d-16 UNDER THE 

SECURITIES EXCHANGE ACT OF 1934

Dated December 2, 2025

Commission File Number 1-14878

GERDAU S.A. 

(Translation of Registrant’s Name into English)

Av. Dra. Ruth Cardoso, 8,501 – 8° andar 

São Paulo, São Paulo - Brazil CEP 05425-070 

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F  x           Form 40-F  ¨ 

Exhibit Index

Exhibit		Description of Exhibit
99.1		Notice to the Market, December 2, 2025

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this Report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: December 2, 2025

	GERDAU S.A.
	By:	/s/ Rafael Dorneles Japur
	Name:	Rafael Dorneles Japur
	Title:	Vice President and Investor Relations Director